Since the end of March, 2007, an unknown number of cat and dog deaths have been attributed to the organic compound melamine. Melamine, a common industrial chemical, is often added to resins to improve flame resistance and has been proposed as an alternative form of fertilizer-N for plant growth. It was found that melamine was intentionally mixed with animal feed, in amounts ranging from 0.2% to 8% of total mass, as a way to boost the products' apparent protein content. Melamine was also used as a binder when making pellet feed for animals. As a result, the impact of melamine contaminated food and animal feed ingredients on food safety and animal health has become a major concern.
In addition to melamine, small amounts of cyanuric acid, ammeline, and ammelide were also detected in pet feed and in the tissue and urine of dead pets that consumed the contaminated food. Although it may be possible that cyanuric acid, ammeline, and ammelilde were added as contaminants, it is more likely that their presence in pet food resulted from the degraded derivatives of melamine.
There is great concern that melamine could again enter the food/feed chain and would be consumed by humans and animals. As part of the Food Protection Plan, US federal agencies, such as the USDA's FSIS and FDA, and other organizations have established the GC-MS and LC-MS/MS procedures for the analysis of melamine in food/feed commodities. Although they might be able to detect melamine contaminant in trace amounts, these time-consuming in-vitro procedures require chemical solvents for the extraction steps and depend on mass spectrometry which is expensive, time-consuming, and labor-intensive.
There exists a need for rapid, non-destructive, specific, low-cost, and routine systems and methods for the detection of melamine. Fast melamine screening requires minimal sample preparation (e.g., no extraction/centrifugation), routine analysis of a number of samples without reagents, minimal procedures and ease of operation. Such systems and methods are increasingly important because of the potential public and animal health concerns. In addition, systems and methods are needed for melamine screening to prevent protein fraud.